scholarly journals LARP6 Meets Collagen mRNA: Specific Regulation of Type I Collagen Expression

2016 ◽  
Vol 17 (3) ◽  
pp. 419 ◽  
Author(s):  
Yujie Zhang ◽  
Branko Stefanovic
1999 ◽  
Vol 277 (5) ◽  
pp. G1074-G1080 ◽  
Author(s):  
Jorge A. Gutierrez ◽  
Hilary A. Perr

Intestinal muscle undergoes stretch intermittently during peristalsis and persistently proximal to obstruction. The influence of this pervasive biomechanical force on developing smooth muscle cell function remains unknown. We adapted a novel in vitro system to study whether stretch modulates transforming growth factor-β1 (TGF-β1) and type I collagen protein and component α1 chain [α1(I) collagen] expression in fetal human intestinal smooth muscle cells. Primary confluent cells at 20-wk gestation, cultured on flexible silicone membranes, were subjected to two brief stretches or to 18 h tonic stretch. Nonstretched cultures served as controls. TGF-β1 protein was measured by ELISA and type I collagen protein was assayed by Western blot. TGF-β1 and α1(I) collagen mRNA abundance was determined by Northern blot analysis, quantitated by phosphorimaging, and normalized to 18S rRNA. Transcription was examined by nuclear run-on assay. Tonic stretch increased TGF-β1 protein 40%, type I collagen protein 100%, TGF-β1 mRNA content 2.16-fold, and α1(I) collagen mRNA 3.80-fold and enhanced transcription of TGF-β1 and α1(I) collagen by 3.1- and 4.25-fold, respectively. Brief stretch stimulated a 50% increase in TGF-β1 mRNA content but no change in α1(I) collagen. Neutralizing anti-TGF-β1 ablated stretch-mediated effects on α1(I) collagen. Therefore, stretch upregulates transcription for TGF-β1, which stimulates α1(I) collagen gene expression in smooth muscle from developing gut.


2002 ◽  
Vol 282 (4) ◽  
pp. F639-F648 ◽  
Author(s):  
Feng Zheng ◽  
Alessia Fornoni ◽  
Sharon J. Elliot ◽  
Youfei Guan ◽  
Matthew D. Breyer ◽  
...  

We found that peroxisome proliferator-activated receptor-γ (PPARγ) mRNA was reduced by 77% in glomeruli of diabetic mice. Because mesangial cells play an important role in diabetic nephropathy, we examined regulation of type I collagen expression by PPARγ and transforming growth factor-β1 (TGF-β1) in mouse mesangial cells in the presence of 6 and 25 mM glucose. Mesangial cells contained functionally active PPARγ. Exposure to 25 mM glucose resulted in reduced PPARγ expression and transcriptional activity, accompanied by increased type I collagen expression. Restoration of PPARγ activity to normal levels in cells cultured in 25 mM glucose, by transfection with a PPARγ expression construct and treatment with the PPARγ agonist troglitazone, returned type I collagen levels toward normal values. Activation of PPARγ by troglitazone also decreased type I collagen mRNA and blocked TGF-β1-mediated upregulation of type I collagen mRNA and protein. Moreover, PPARγ activation suppressed basal and activated TGF-β1 responses in mesangial cells. This action was blocked by transfection of cells with a dominant-negative PPARγ construct. In summary, PPARγ suppresses the increased type I collagen mRNA and protein expression mediated by TGF-β1 in mesangial cells.


Development ◽  
1993 ◽  
Vol 117 (1) ◽  
pp. 245-251
Author(s):  
R. Quarto ◽  
B. Dozin ◽  
P. Bonaldo ◽  
R. Cancedda ◽  
A. Colombatti

Dedifferentiated chondrocytes cultured adherent to the substratum proliferate and synthesize large amounts of type I collagen but when transferred to suspension culture they decrease proliferation, resume the chondrogenic phenotype and the synthesis of type II collagen, and continue their maturation to hypertrophic chondrocyte (Castagnola et al., 1986, J. Cell Biol. 102, 2310–2317). In this report, we describe the developmentally regulated expression of type VI collagen in vitro in differentiating avian chondrocytes. Type VI collagen mRNA is barely detectable in dedifferentiated chondrocytes as long as the attachment to the substratum is maintained, but increases very rapidly upon passage of the cells into suspension culture reaching a peak after 48 hours and declining after 5–6 days of suspension culture. The first evidence of a rise in the mRNA steady-state levels is obtained already at 6 hours for the alpha 3(VI) chain. Immunoprecipitation of metabolically labeled cells with type VI collagen antibodies reveals that the early mRNA rise is paralleled by an increased secretion of type VI collagen in cell media. Induction of type VI collagen is not the consequence of trypsin treatment of dedifferentiated cells since exposure to the actin-disrupting drug cytochalasin or detachment of the cells by mechanical procedures has similar effects. In 13-day-old chicken embryo tibiae, where the full spectrum of the chondrogenic differentiation process is represented, expression of type VI collagen is restricted to the articular cartilage where chondrocytes developmental stage is comparable to stage I (high levels of type II collagen expression).(ABSTRACT TRUNCATED AT 250 WORDS)


Gene ◽  
2019 ◽  
Vol 685 ◽  
pp. 32-41 ◽  
Author(s):  
Er-meng Yu ◽  
Ling-ling Ma ◽  
Hong Ji ◽  
Zhi-fei Li ◽  
Guang-jun Wang ◽  
...  

1989 ◽  
Vol 9 (5) ◽  
pp. 2224-2227
Author(s):  
R A Rippe ◽  
S I Lorenzen ◽  
D A Brenner ◽  
M Breindl

We have identified two blocks of regulatory sequences located in the 5'-flanking region and the first intron of the mouse alpha 1 type I collagen (COL1A1) gene. Both blocks were found to contain positive as well as negative regulatory elements. Sequences located within 222 base pairs upstream of the transcription start site showed a strong stimulatory effect on the COL1A1 promoter and were sufficient for tissue-specific regulation of the COL1A1 gene. The combined upstream and intron regulatory sequences showed a marked inhibition of COL1A1 promoter activity in fibroblasts. This finding suggests that additional, more remote regulatory sequences may be required for establishing the high level of activity of the endogenous COL1A1 gene in fibroblastoid cells.


Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2876
Author(s):  
Poh-Shiow Yeh ◽  
Jui-Tai Chen ◽  
Yih-Giun Cherng ◽  
Shun-Tai Yang ◽  
Yu-Ting Tai ◽  
...  

An estrogen deficiency is the main cause of osteoporosis in postmenopausal women. In bone remodeling, estrogen receptors (ERs) can mediate estrogen-transducing signals. Methylpiperidinopyrazole (MPP) is a highly specific antagonist of ER-alpha (ERα). This study was designed to evaluate the effects of MPP on estrogen-induced energy production, subsequent osteoblast maturation, and the possible mechanisms. Exposure of primary osteoblasts isolated from neonatal rat calvarias to MPP did not affect cell morphology or survival. Estradiol can induce translocation of ERα into mitochondria from the cytoplasm. Interestingly, pretreatment of rat calvarial osteoblasts with MPP lowered estrogen-induced ERα translocation. Sequentially, estrogen-triggered expressions of mitochondrial energy production-linked cytochrome c oxidase (COX) I and COX II messenger (m)RNAs were inhibited following pretreatment with MPP. Consequently, MPP caused decreases in estrogen-triggered augmentation of the activities of mitochondrial respiratory complex enzymes and levels of cellular adenosine phosphate (ATP). During progression of osteoblast maturation, estrogen induced bone morphogenetic protein (BMP)-6 and type I collagen mRNA expressions, but MPP treatment inhibited such induction. Consequently, estrogen-induced osteoblast activation and mineralization were attenuated after exposure to MPP. Taken together, MPP suppressed estrogen-induced osteoblast maturation through decreasing chromosomal osteogenesis-related BMP-6 and type I collagen mRNA expressions and mitochondrial ATP synthesis due to inhibiting energy production-linked COX I and II mRNA expressions. MPP can appropriately be applied to evaluate estrogen-involved bioenergetics and osteoblast maturation.


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